Lexington and Seoul

I live in Lexington, Massachusetts. I went back to Korea this summer vacation. When I arrived I knew right away the difference of the air. In Lexington, the air was so clean and fresh. I think because there are many trees out there. But, in Seoul, Korea (Seoul is a very big city, with a population of 10,373,234), the air was kind of dirty in a way compared to Lexington. The strange thing was, when I was jumping rope in Seoul, after 600 jumps, my breathing was tough, but when I jumped rope in Boston (after the summer vacation) I had no problem after 1000 jumps. I think it is much easier to jump rope in Boston, because when I go outside from my apartment, I can only see trees, grass, and dirt. I think these make the air fresh. If you want to see some buildings you have to drive at least for 15 minutes. But when you are in Seoul, all you can see are tall apartments, tall buildings (which contain lots and lots of academies), and busy streets. Of course we have trees but, not as many as America.